Blandfoder eller separat utfodring till mjölkkor i AMS med fri kotrafik

Sammanfattning: The aim of the study was to compare two feeding strategies, partial mixed ration (PMR) and separate feeding (SR) of grass/clover silage and concentrate, and find out how feed intake, milking frequency and milk production was affected when the cows were milked in an automatic milking system (AMS) with free cow traffic. The study included 38 cows in early to mid lactation divided into two groups fed PMR or SR and lasted for ten weeks. The PMR group was fed a mix consisting of silage and concentrate, and received additional concentrate in the milking robot. The mix contained 35% concentrate and 65% silage on dry matter (DM) basis. The SR group was offered silage in feed troughs and concentrate was supplied both in concentrate dispensers and in the robot during milking. All cows were fed according to the standards for organic milk production, i.e. up to 90 days in milk they received maximum 50% of total DMintake in the form of concentrate and after 90 days in milk they received maximum 40% concentrate. Cows with more than 13 hours milking interval were fetched manually at four set times each day. Cows in the PMR group voluntarily visited the milking robot significantly more often than the SR cows, in average 2.6 and 2.3 times per day, respectively. Fewer cows needed to be fetched manually in PMR compared with SR. When comparing the cell count, milk yield and milk composition there were no differences between the groups: 50 × 10³ and 31×10³ cells/ml, 35.0 and 35.4 kg energy corrected milk, 4.12 and 4.05 % milk fat and 3.44 and 3.47 % milk protein, in PMR and SR, respectively. The PMR group consumed significantly more feed than the SR group, 26.8 and 24.0 kg DM per cow and day, respectively, but no differences in body weight change or change in body condition were detected between the groups. The reason for higher intake in the PMR group may be that the mix was more palatable to the cows compared to silage. The higher milking frequency in the PMR group may be due to increased motivation to visit the robot since it was the only place where they could find concentrate.